Current policy neglects to anticipate the impact of floodplain development on future flood potential.

Flood disasters have been addressed by a combination of
policies and programs over the decades, with calls for reform after
each major disaster. The recommendations made in 1994 were the latest
such wave, and efforts to implement those recommendations have met
with partial success.

But there is a growing perception that these efforts are doomed
to fail because they're focused on yesterday's floodplain. Much
of current flood policy looks backwardusing old floodplain
maps that don't show existing structures, analyzing historic flood
patterns that yield limited insight about tomorrow's floods and
extrapolating from prior decade meteorological data in an era of
global climate change.

In that sense, flood policy is still fighting the last flood. "We're
not taking into consideration the impacts of additional development
on existing and future flooding," noted Larry Larson, executive
director of the Association of State Floodplain Managers. "We
talk about today's floodplain, not tomorrow's."

Current efforts to control river flow or curb human incursion into
the floodplains will not adequately anticipate changes in those
flows and floodplains, says Larson, and the result will be continued
escalation in flood disaster losses. "We worry about how to
build in the floodplain," he said, by requiring elevated structures.
"But we don't worry about how other development in the watershed
is going to change that floodplain."

A plan for a dam on the Maple River in North Dakota provides a
good example. If it's built, the dam might initially protect downstream
homes like Carol Hallett's in the town of Harwood, near Fargo. Hallett,
who runs a day-care center out of her home, has suffered floods
twice in the last decade and like many others in Harwood she thinks
a dam would offer a permanent solution.

But if more farmers in the Maple River watershed tile and drain
their fields, or if a new dam convinces developers to build housing
and shopping centers on the "protected" floodplain, then
rooftops and parking lots will replace fields, and spring rains
will rush off the new impermeable surfaces rather than being absorbed.
Development will have changed the floodplain and Carol Hallett's
day-care might again close down due to flooding.

Some flood analysts say it makes sense to at least consider devoting
public dollars to encouraging development outside the floodplain,
rather than spending that money on dams, levees, floodwalls and
mitigation to protect structures within it. "Our obligation
is to rethink the patterns of urban and floodplain land use which
have created so much vulnerability," writes John Weiner, a
research associate at the Program on Environment and Behavior at
the University of Colorado.

But more immediately, said Larson, is the obligation to ensure
that anyone who does develop within the floodplain pays the full
cost of doing so, and that includes the impact that structure will
have on others in future floods.

"In Wisconsin," said the Madison-based Larson, "we
made sure that everyone [whose project would] cause any increase
in flood levels ... identified every piece of property that's impacted
by the increase, and got flooding easements from every one of those
property owners." When Green Bay road builders recently wanted
to build a bridge, he says by way of example, they were forced to
negotiate an easement price with each property owner who would be
affected by that bridge's impact on the floodplain. Instead they
changed the bridge design so it wouldn't have a flood impact.

The approach sounds painfully bureaucratic, but it's a way to create
a price, in advance, for the cost of increasing flood hazards. "The
market determines the value," noted Larson, by putting those who
would incur the cost of increased flood hazards in negotiation with those
who create that hazard. An economist would say that such a floodplain
regulation forces floodplain developers to internalize the externalities.
The rest of us would say that everyone has to pull their own weight, cover
their costs: If you're doing something that will contribute to a flood,
pay the price. Anything less is shifting the burden to a future flood
victim. Or the taxpayer.